In particulary, look at the runTransformOnXXX family of methods, which can
load your model from a workspace resource (runTransformOnResource), from a
string representation of your resource (runTransformOnString), or from an
in-memory representation of your model (runTransformOnObject).

From your stack trace, it appears that you are not running within Eclipse.
If so, then this is your problem.

JET has dependencies on Eclipse. It is not sufficient to just include all
the required Eclipse plug-ins in your ClassPath. JET requires an active
Eclipse/OSGi runtime.

This doesn't mean that you must have the Eclipse UI visible, but it does
mean that your code needs to be in an Eclipse plug-in, and that you need
to start an Eclipse instance rather than just a Java JVM to run your code.

Assuming you are not interested in using the Eclipse UI, then take a look
at the org.eclipse.core.runtime.applications extension point:

Your test program may launched from Eclipse, but it is NOT running in an
active Eclipse instance. I can tell by looking at your stack trace - it
starts from a 'main' method in one of your classes - Eclipse plug-ins
don't typically do this:

1) create a new Plug-in project:
a) Click File > New > Project ... Select Plug-in Project
b) Enter a plug-in name (e.g. com.myorg.testjet). Click Next
c) In the second wizard page, ensure 'This plug-in will make
contributions to the UI' is checked. Click Next.
d) On the 'Templates' wizard page, select 'Hello, World Command'. Click
Finish. (Instead of clicking Finish, you can click Next, and change the
names of some of the things generated.)

4) Run your test code in an Eclipse Application (also known as an Eclipse
Runtime workbench):
a) Click Run > Run Configurations
b) Select 'Eclipse Application' and the 'new' icon
c) I suggest you give the 'configuration' a more meaningful name than
'New_configuration'. Something like: "test programmatic JET invocation'.
d) Click Run. A second instance of Eclipse will start - it will include
your test code.
e) You can invoke your test code by clicking Sample Menu > Sample
Command

Tip. You might want to show the Error Log view (Window > Show View >
Other, then look for General > Error Log). Errors such as failing to open
the EMF Resource will only show up in the error log.

Lastly, I am guessing you are new to Eclipse development. I still find the
Eclipse FAQ very useful:

Using the following code you gave me:
"StatusManager.getManager().handle(status);"

Then, it shew me the error log and I found the mistake. The issue was that
when I was trying to find out, I had added some code everywhere and I had
forgotten to remove something then.

Now, the project runs very well. I thank you so much.

I have just finished my studies and I've been employed by a company as
trainee. My manager wants me to work and earn skills on modeling tool.
They are no people in the company that is really qualified in modeling
project.
Then, thank's for your help.